Rigor mortis in human body starts at

Ans. d (Eyelids)RIGOR MORTIS# Ordinarily, death is followed immediately by total muscular relaxation - primary muscular flaccidity - succeeded in turn by generalised muscular stiffening - rigor mortis.# After a variable period of time rigor mortis passes off spontaneously; followed by secondary muscular flaccidity.# The first investigation on rigor mortis is attributed to Nysten in 1811.# No measurable shortening of muscle occurs during rigor mortis unless the muscles are subjected to tension.# The view that the development of rigor mortis could produce significant movements of the body was promoted by Sommer, in about 1833, and the postulated movements became known as "Sommer's movements". For this reason, when a body is found in a certain position with rigor mortis fully developed, it cannot be assumed that the deceased necessarily died in that position.# Rigor involves voluntary and involuntary muscles.# Contraction of the arrectores pilorum muscles during rigor may result in "goose-flesh" or "cutis anserina". The phenomenon is commonly seen in cases of drowning where it is thought to result from an agonal contraction of the muscles.# Involvement of walls of seminal vesicles by rigor may lead to discharge of seminal fluid at the glans penis.# In individuals who have been exhausted or starved before death, the glycogen stores in muscle are low, so that rigor may develop rapidly.# Typically, rigor is first apparent in small muscles of eyelids, lower jaw and neck, followed by the limbs.# It is generally accepted that rigor mortis passes off in the same order in which it develops.# In temperate climates rigor will typically start to disappear at about 36-48 hours after death. However, if the environ- mental temperature is high then the development of putrefaction may completely displace rigor within 9-12 hours of death.# Accelerated putrefaction resulting from ante-mortem septicaemia may lead to a rapid displacement of rigor.# Exposure of a body to intense heat results in heat stiffening due to coagulation of the muscle proteins. Unlike rigor mortis, heat stiffening is associated with muscle shortening resulting in the characteristic pugilistic posture of burned bodies.# Freezing of a body will cause stiffening of the muscles, postponing the development of rigor which is said to developed as soon as thawing of the body permits.